1. Field of the Invention
This invention relates to an electrical connector including a conductive section and an insulative cover for connection of a temporary cardiac pacing wire to external equipment.
2. Description of Related Art
Temporary cardiac pacing wires typically have one end attached to the heart during surgery and the opposite end passes through the chest with a portion exterior to the body. To aid in passing through the chest, a temporary cardiac pacing wire has a needle on the end not attached to the heart. A straight needle, also known as a Keith needle, is typically used to penetrate the chest wall from the interior and pull a portion of the temporary pacing wire outside of the body. In order to connect the body exterior end of the temporary pacing wire to pacing and/or monitoring equipment, it is necessary to create an electrical connection on the exterior exposed portion of the temporary pacing wire. Once this step is complete, the temporary pacing wire creates a direct, electrical connection to the surface of the heart. As such, the body exterior termination of the temporary pacing wire should be fully electrically insulated for safety reasons and environmentally isolated from liquids and other contaminates that may degrade its performance both when it is connected to the external equipment and especially when it is not as it is not uncommon for the temporary pacing wire to be unconnected to the external equipment for long periods of time.
The current practice to create this body exterior temporary pacing wire termination utilizes one of two methods.
The first, and most common method, illustrated in FIGS. 1A and 1B, creates the termination by utilizing the already existing Keith needle 12 used to pass the wire 10 through the chest of the patient. The needle 12 is mechanically and electrically attached to the pacing wire 10 during manufacture. After the needle 12 has been passed through the chest, it itself forms the termination. The needle 12 can then be cut at location 16 with a pair of diagonal snips or pliers 14 leaving a stub 18 as the electrical termination, however, the entire needle 12 could also be used as a less convenient “stub”. Alternatively, as shown in FIG. 1B, the needle 12 could include a weakened zone 22 that can be snapped by the hands of a user 20 to produce the stub 18.
The stub 18 is then electrically insulated and sealed from the environment using a combination of improvised materials such as adhesive tape, the finger of a surgical glove, a syringe cover, a tongue depressor, and the like. When it is time for the pacing wire 10 to be connected to the external equipment, the cumbersome insulating and sealing materials must be removed to expose the stub 18. A variety of connecting cables are then used which accept the stub 18 on one end and connect it to external equipment on the other. Unfortunately, the cables do not provide a 100% electrically insulated connection, nor do they protect the connection from the environment.
U.S. Pat. No. 4,442,840, issued to Alexander Wojciechowicz, Jr. on Apr. 17, 1984, teaches an apparatus which can accept the stub pacing wire termination and both electrically insulate and environmentally isolate the stub. However, in order to connect to the external equipment, a proprietary cable must be used. It does not offer a direct connection to the external equipment. The above apparatus taught in U.S. Pat. No. 4,442,840 also uses small removable components which are easily misplaced and once missing cause the electrical insulating and environmentally isolating properties to be eliminated.
A second method of termination is taught by U.S. Pat. No. 4,693,258. It also uses a needle to pass the temporary pacing wire 10 through the chest and exterior of the body. To form its terminal connection, the pacing wire 10 must have a portion of its insulation removed immediately adjacent to the needle 12. The needle 12 is then passed through a hole in an electrically conductive pin. The needle 12 is then cut off and an insulating sleeve is passed around the pin and bare wire. The compression of the sleeve around the pin maintains the electrical contact between the exposed conductor of the pacing wire and the pin. This method allows direct connection to the external equipment, however, it does not create an electrically insulated or environmentally isolated connection as the portion of the pin which does not plug into the external equipment is uncovered and often times the uninsulated conductor of the pacing wire is also exposed due to errors in the placement of the cut when removing the needle during assembly of the apparatus.
One of the more relevant inventions is found in U.S. Pat. No. 6,644,998, entitled “Electrical Connecting Element”, issued to Kaufmann et al. Described therein is a connector for a wire lead extending from the heart muscle, out of the body, and towards an external heart pacemaker. Apparently there is no needle on the end of the wire lead which passes through the exterior of the patient's body. Accordingly, this connector engages a lead end, rather than a needle, connected to a lead end. The connector is intended to engage an insulated wire lead end which is inserted through a clamping sleeve and into engagement with a squeezing contact element held by an insulation sleeve which mates with the clamping sleeve. The mating of the clamping sleeve and the insulation sleeve forces a squeezing contact element into the insulation making electrical contact with the wire lead.
Similarly, U.S. Pat. No. 6,397,108, entitled “Safety Adaptor for Temporary Medical Leads” and issued to Camps et al describes an adaptor for attaching a temporary cardiac pacing lead or analogous lead to a pacemaker or other apparatus exterior to the patient. According to one embodiment of the invention, an elongate assembly comprises a body and a door hinge together along a side edge that cooperates to receive and contain a lead including a Keith-type needle which is broken off after the lead end is inserted in the assembly. The assembly is provided with contacts which enable the assembly, upon insertion into a receptacle exterior to the apparatus, to communicate signals between the exterior apparatus and the lead contained in the assembly.
U.S. Pat. No. 6,021,355, entitled “Surgical Electrode Having a Partially Insulated Needle”, issued to Slichervinsky, discloses a device in which the insulation protected end of a temporary cardiac pacing wire exits the patient's body and is intended for connection to an external pacemaker.
U.S. Pat. No. 5,350,419, entitled “Cardiac Pacing Lead”, issued to Bendel, at al describes a device which provides a direction connection between the remaining portion of a Keith-type needle and an exterior apparatus.
U.S. Pat. No. 6,254,425, entitled “Electrical Connector for Cardiac Devices”, issued to Slichervinsky et al, likewise describes a temporary cardiac pacing wire, including multiple conductive sections, wherein a Keith-type needle is broken to create a segment to plug into an exterior pacemaker. A branch electrode wire is inserted into a blind hole at one end of an elongate conductive wire segment to form a connector which also plugs into the pacemaker.
Finally, note U.S. patent application Publication US 2003/0040784-A1, published on Feb. 27, 2003, and entitled “Medical Lead Adapter for Storing, Isolating, Identifying and Connecting Temporary Pacing Leads” is of general interest and teaches background that relates to the general state of the prior art.
While the prior art does appear to disclose a variety of different devices for connecting a lead to a temporary cardiac pacing device, nevertheless, there does not appear to be a truly efficient and effective connector to terminate, insulate, and environmentally isolate a temporary cardiac pacing wire to the satisfaction of the surgeons that employ them and the patients that use them.
It was in the context of the foregoing prior art that the present invention arose.